1. Field of the Invention
The invention relates to a device and method for profiling railway rails and, more particularly, to a device and method for vehicle wheel profile-matching railway turnouts and crossings.
2. Description of Related Art
The contact rolling surface found along the length of a standard railway crossing, such as a steel frog or a diamond crossing, has been pre-defined for many years. When a vehicle passes through a typical rail crossover, the wheels pass over a raised wing surface, which is designed to support and maintain the wheel profile for a relatively level passage. Rail crossover, as used herein, means a rail turnout or crossing allowing a rail vehicle to be guided from one set of rails to another. Insert and solid steel frog designs have been supplied for many years and are used by every major railway. Very little advancement has taken place with regard to technology designed to precisely match an existing rail crossover to a specific existing vehicle wheel profile or to alternate wheel profiles. Vehicle wheel widths and tapered tread profiles are often custom designed to suite a particular transit operator's requirements. As a result, when a standard crossover design is installed, oftentimes the transfer surfaces are not continuously levelly supported through the entire length of the crossover casting. Without matching the crossover profile to the wheel requirements, level rolling discontinuities often result in dropping of the wheel tread surface, thereby, imparting high impacted forces and accelerated wear/damage to the track and vehicle bogie system. Bogie impact forces, from as little as 5 mm of height, have resulted in up to 30-40 G of impact force during higher vehicle operating speeds and significantly have reduced operating life expectancy for track and vehicle components.
When field repair is required on a damaged crossover, rolling surface areas are built-up through a special certified welding process and the profile manually shaped back to the original (usually flat) profile with a hand grinder. The finished surface contour is usually visually inspected with a straight edge to verify that the finished product is returned as close as possible to the original rail surface contour. Without a technique to accurately apply and precisely shape the length of the crossover to a fully level supported “wheel tread matching” profile, and without an accurate means to quickly and easily verify an alternate properly supporting profile has been provided, rolling axle instability due to wheel passage and track/equipment wear will continue to occur.
Typical technology used to shape the crossover surface after welding includes grinding by use of a hand grinder or portable grinding platforms that are either secured directly over the crossover casting or are guided to provide a flat and level profile over a relatively short linear path. However, after grinding a section, the finished surface is only visually inspected and checked with a straight edge or simple hand tools to ensure reworked sections are uniform with no surface gaps present. These methods do not apply to a revised raised wing or point sections to better support the transfer of the wheel path. Therefore, wheel load impacts are not prevented, only maintained at a lower level after rework. This results in less accurate correction to the surface profiles of the crossovers with limited verification. Often, surface discontinuities are still present after modification resulting again with initially lower impact forces. The previously used methods included minor modifications, which failed to correct the source of the impact forces.
These high impact forces have often led to the reduction of operating speeds through crossovers and continuous repair and maintenance for both vehicles and rails. The cost and time required to routinely repair rail crossovers is an ongoing concern.
There exists a need for a precision and efficient method and device to greatly eliminate impact forces due to imperfectly matched rail crossover profiles and vehicle wheel profiles.